Subzero: Fix the name mangling code's base-36 increment.

tests_lit/llvm2ice_tests/mangle.ll

 ; Tests the Subzero "name mangling" when using the "llvm2ice --prefix"
 ; option.
 
 ; RUN: %llvm2ice --verbose none %s | FileCheck %s
 ; RUN: %llvm2ice --verbose none --prefix Subzero %s | FileCheck --check-prefix=MANGLE %s
 ; RUN: %llvm2ice --verbose none %s | FileCheck --check-prefix=ERRORS %s
 ; RUN: %llvm2iceinsts %s | %szdiff %s | FileCheck --check-prefix=DUMP %s
 ; RUN: %llvm2iceinsts --pnacl %s | %szdiff %s \
 ; RUN:                           | FileCheck --check-prefix=DUMP %s
 
@@ skipping 87 matching lines @@
 define internal void @_Z-1FuncCPlusPlusi(i32 %i) {
 entry:
   ret void
 }
 ; MANGLE: Subzero_Z-1FuncCPlusPlusi:
 
 
 ; Test for substitution incrementing.  This single test captures:
 ;   S<num>_ ==> S<num+1>_ for single-digit <num>
 ;   S_ ==> S0_
-;   String length increase, e.g. SZZZ_ ==> S0000_
+;   String length increase, e.g. SZZZ_ ==> S1000_
 ;   At least one digit wrapping without length increase, e.g. SZ9ZZ_ ==> SZA00_
 ;   Unrelated identifiers containing S[0-9A-Z]* , e.g. MyClassS1x
 ;   A proper substring of S<num>_ at the end of the string
 ;     (to test parser edge cases)
 
 define internal void @_Z3fooP10MyClassS1xP10MyClassS2xRS_RS1_S_S1_SZZZ_SZ9ZZ_S12345() {
-; MANGLE:   _ZN7Subzero3fooEP10MyClassS1xP10MyClassS2xRS0_RS2_S0_S2_S0000_SZA00_S12345:
+; MANGLE:   _ZN7Subzero3fooEP10MyClassS1xP10MyClassS2xRS0_RS2_S0_S2_S1000_SZA00_S12345:
 entry:
   ret void
 }
 
 ; Test that unmangled (non-C++) strings don't have substitutions updated.
 define internal void @foo_S_S0_SZ_S() {
 ; MANGLE:   Subzerofoo_S_S0_SZ_S:
 entry:
   ret void
 }
 
 ; ERRORS-NOT: ICE translation error
 ; DUMP-NOT: SZ