Change MemMap::maps_ to not be global variable

Runtime.exit() was causing globals to get destructed at the same time
that another thread was using it for allocating a new mem map.

(cherry picked from commit 6e88ef6b604a7a945a466784580c42e6554c1289)

Bug: 17962201
Change-Id: I400cb7b8141d858f3c08a6fe59a02838c04c6962
diff --git a/runtime/mem_map_test.cc b/runtime/mem_map_test.cc
index 69f618c..5ec3335 100644
--- a/runtime/mem_map_test.cc
+++ b/runtime/mem_map_test.cc
@@ -85,6 +85,10 @@
     delete m1;
   }
 
+  void CommonInit() {
+    MemMap::Init();
+  }
+
 #if defined(__LP64__) && !defined(__x86_64__)
   static uintptr_t GetLinearScanPos() {
     return MemMap::next_mem_pos_;
@@ -99,10 +103,10 @@
 #endif
 
 TEST_F(MemMapTest, Start) {
+  CommonInit();
   uintptr_t start = GetLinearScanPos();
   EXPECT_LE(64 * KB, start);
   EXPECT_LT(start, static_cast<uintptr_t>(ART_BASE_ADDRESS));
-
 #ifdef __BIONIC__
   // Test a couple of values. Make sure they are different.
   uintptr_t last = 0;
@@ -120,6 +124,7 @@
 #endif
 
 TEST_F(MemMapTest, MapAnonymousEmpty) {
+  CommonInit();
   std::string error_msg;
   std::unique_ptr<MemMap> map(MemMap::MapAnonymous("MapAnonymousEmpty",
                                              nullptr,
@@ -141,6 +146,7 @@
 
 #ifdef __LP64__
 TEST_F(MemMapTest, MapAnonymousEmpty32bit) {
+  CommonInit();
   std::string error_msg;
   std::unique_ptr<MemMap> map(MemMap::MapAnonymous("MapAnonymousEmpty",
                                              nullptr,
@@ -155,6 +161,7 @@
 #endif
 
 TEST_F(MemMapTest, MapAnonymousExactAddr) {
+  CommonInit();
   std::string error_msg;
   // Map at an address that should work, which should succeed.
   std::unique_ptr<MemMap> map0(MemMap::MapAnonymous("MapAnonymous0",
@@ -200,6 +207,7 @@
 TEST_F(MemMapTest, MapAnonymousExactAddr32bitHighAddr) {
   uintptr_t start_addr = ART_BASE_ADDRESS + 0x1000000;
   std::string error_msg;
+  CommonInit();
   std::unique_ptr<MemMap> map(MemMap::MapAnonymous("MapAnonymousExactAddr32bitHighAddr",
                                              reinterpret_cast<byte*>(start_addr),
                                              0x21000000,
@@ -212,6 +220,7 @@
 }
 
 TEST_F(MemMapTest, MapAnonymousOverflow) {
+  CommonInit();
   std::string error_msg;
   uintptr_t ptr = 0;
   ptr -= kPageSize;  // Now it's close to the top.
@@ -227,6 +236,7 @@
 
 #ifdef __LP64__
 TEST_F(MemMapTest, MapAnonymousLow4GBExpectedTooHigh) {
+  CommonInit();
   std::string error_msg;
   std::unique_ptr<MemMap> map(MemMap::MapAnonymous("MapAnonymousLow4GBExpectedTooHigh",
                                              reinterpret_cast<byte*>(UINT64_C(0x100000000)),
@@ -239,6 +249,7 @@
 }
 
 TEST_F(MemMapTest, MapAnonymousLow4GBRangeTooHigh) {
+  CommonInit();
   std::string error_msg;
   std::unique_ptr<MemMap> map(MemMap::MapAnonymous("MapAnonymousLow4GBRangeTooHigh",
                                              reinterpret_cast<byte*>(0xF0000000),
@@ -252,6 +263,7 @@
 #endif
 
 TEST_F(MemMapTest, CheckNoGaps) {
+  CommonInit();
   std::string error_msg;
   constexpr size_t kNumPages = 3;
   // Map a 3-page mem map.