[Local GC] Remove static fields from GC interface (#10566)

* Remove max_generation from GC interface

* [Local GC] Clean up the GC interface by removing all static fields
from it:
  1) gcHeapType is replaced by g_heap_type (EE side) and g_gc_heap_type
     (GC side), each of which is set on initialization. g_heap_type is
     read by the DAC to determine what kind of heap is being used.
  2) maxGeneration is not necessary due to the GC DAC changes.

* Rebase against master

* Comments and cleanup

* Use a heap allocation instead of alloca

* Code review feedback: remove a redundant cast and allocate generation count table once, on first use

* Address code review feedback: cache some calls to GetMaxGeneration

1 files changed, 1 insertions, 0 deletions

diff --git a/src/vm/gcheaputilities.cpp b/src/vm/gcheaputilities.cpp
index 730728927a..91640d30a2 100644
--- a/src/vm/gcheaputilities.cpp
+++ b/src/vm/gcheaputilities.cpp
@@ -14,6 +14,7 @@
 GPTR_IMPL_INIT(uint32_t, g_card_table,      nullptr);
 GPTR_IMPL_INIT(uint8_t,  g_lowest_address,  nullptr);
 GPTR_IMPL_INIT(uint8_t,  g_highest_address, nullptr);
+GVAL_IMPL_INIT(GCHeapType, g_heap_type,     GC_HEAP_INVALID);
 uint8_t* g_ephemeral_low  = (uint8_t*)1;
 uint8_t* g_ephemeral_high = (uint8_t*)~0;