Request for reviews (S): 6896381: CTW fails share/vm/ci/bcEscapeAnalyzer.cpp:99, assert(_stack_height < _max_stack,"stack overflow")

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/6896381/webrev

Fixed 6896381: CTW fails share/vm/ci/bcEscapeAnalyzer.cpp:99, assert(_stack_height < _max_stack,"stack overflow")

Bytecode Analyzer emulates stack usage to track
objects reference. For constants load (ldc) it
loads a constant from constant pool to check its
type but it does not check T_ILLEGAL type returned
for unloaded strings and klasses when no space left
in PermGen.

Solution:
Check constant Tag type instead since we need
to know only constant's type.
Also changed asserts to guarantee to avoid memory
stomp in product VM.

Tested with CTW.