Refactor the JIT to be object-oriented (#1879)

* Move TinyVector to a new file

- So it's less sensitive to #include ordering

* Forgot to include assert.h

* Refactor ARMJIT_Memory into an object

* Oops, forgot a declaration

* Refactor ARMJIT to be contained in an object

* Remove an unused function declaration

* Add a missing #include

* Remove a now-unused global

* Use ARMJIT_Memory's own memory access functions

* Fix some omissions in the ARM JIT

* Move libandroid to be a member of ARMJIT_Memory instead of a global

* Default-initialize most fields in ARMJIT_Compiler.h

* Define NOOP_IF_NO_JIT

* Finish refactoring the JIT to be object-oriented

src/ARMJIT_Compiler.h

@@ -19,6 +19,12 @@
 #ifndef ARMJIT_COMPILER_H
 #define ARMJIT_COMPILER_H
 
+#ifdef JIT_ENABLED
+#define NOOP_IF_NO_JIT
+#else
+#define NOOP_IF_NO_JIT {}
+#endif
+
 #if defined(__x86_64__)
 #include "ARMJIT_x64/ARMJIT_Compiler.h"
 #elif defined(__aarch64__)
@@ -27,9 +33,4 @@
 #error "The current target platform doesn't have a JIT backend"
 #endif
 
-namespace ARMJIT
-{
-extern Compiler* JITCompiler;
-}
-
 #endif