Add MethodImplOptions.AggressiveOptimization and use it for tiering

Part of fix for https://github.com/dotnet/corefx/issues/32235
Workaround for https://github.com/dotnet/coreclr/issues/19751
- Added and set CORJIT_FLAG_AGGRESSIVE_OPT to indicate that a method is flagged with AggressiveOptimization
- For a method flagged with AggressiveOptimization, tiering uses a foreground tier 1 JIT on first call to the method, skipping the tier 0 JIT and call counting
- When tiering is disabled, a method flagged with AggressiveOptimization does not use r2r-pregenerated code
- R2r crossgen does not generate code for a method flagged with AggressiveOptimization

src/System.Private.CoreLib/shared/System/Runtime/CompilerServices/MethodImplOptions.cs

@@ -16,6 +16,7 @@ public enum MethodImplOptions
  NoOptimization = 0x0040,
  PreserveSig = 0x0080,
  AggressiveInlining = 0x0100,
+ AggressiveOptimization = 0x0200,
  InternalCall = 0x1000
  }
 }

src/ilasm/asmparse.y

@@ -78,7 +78,7 @@
 %token VALUE_ VALUETYPE_ NATIVE_ INSTANCE_ SPECIALNAME_ FORWARDER_
 %token STATIC_ PUBLIC_ PRIVATE_ FAMILY_ FINAL_ SYNCHRONIZED_ INTERFACE_ SEALED_ NESTED_
 %token ABSTRACT_ AUTO_ SEQUENTIAL_ EXPLICIT_ ANSI_ UNICODE_ AUTOCHAR_ IMPORT_ ENUM_
-%token VIRTUAL_ NOINLINING_ AGGRESSIVEINLINING_ NOOPTIMIZATION_ UNMANAGEDEXP_ BEFOREFIELDINIT_
+%token VIRTUAL_ NOINLINING_ AGGRESSIVEINLINING_ NOOPTIMIZATION_ AGGRESSIVEOPTIMIZATION_ UNMANAGEDEXP_ BEFOREFIELDINIT_
 %token STRICT_ RETARGETABLE_ WINDOWSRUNTIME_ NOPLATFORM_
 %token METHOD_ FIELD_ PINNED_ MODREQ_ MODOPT_ SERIALIZABLE_ PROPERTY_ TYPE_
 %token ASSEMBLY_ FAMANDASSEM_ FAMORASSEM_ PRIVATESCOPE_ HIDEBYSIG_ NEWSLOT_ RTSPECIALNAME_ PINVOKEIMPL_
@@ -854,6 +854,7 @@ implAttr : /* EMPTY */ { $$ = (CorMethodImp
  | implAttr NOINLINING_ { $$ = (CorMethodImpl) ($1 | miNoInlining); }
  | implAttr AGGRESSIVEINLINING_ { $$ = (CorMethodImpl) ($1 | miAggressiveInlining); }
  | implAttr NOOPTIMIZATION_ { $$ = (CorMethodImpl) ($1 | miNoOptimization); }
+ | implAttr AGGRESSIVEOPTIMIZATION_ { $$ = (CorMethodImpl) ($1 | miAggressiveOptimization); }
  | implAttr FLAGS_ '(' int32 ')' { $$ = (CorMethodImpl) ($4); }
  ;