core/vm: fix typo callInexistant -> callInexistent in runtime_test.go

[Caplost]

Fix typo: callInexistant -> callInexistent in runtime_test.go

Summary

This PR fixes a spelling error in the variable name callInexistant which should be callInexistent (meaning "nonexistent").

Changes

• File: core/vm/runtime/runtime_test.go
• Change: Renamed variable callInexistant to callInexistent (lines 455 and 495)
• Type: Spelling/typo fix
• Impact: Code readability improvement, no functional changes

Details

The variable callInexistant was incorrectly spelled. The correct spelling is callInexistent, which properly conveys the meaning that it's calling a nonexistent contract address (0xff) for benchmarking purposes.

Before:

callInexistant := p.
    Call(nil, 0xff, 0, 0, 0, 0, 0).
    Op(vm.POP).Jump(lbl).Bytes()

benchmarkNonModifyingCode(100000000, callInexistant, "call-nonexist-100M", "", b)

After:

callInexistent := p.
    Call(nil, 0xff, 0, 0, 0, 0, 0).
    Op(vm.POP).Jump(lbl).Bytes()

benchmarkNonModifyingCode(100000000, callInexistent, "call-nonexist-100M", "", b)

Testing

• [x] No functional changes, only variable naming
• [x] Existing tests should continue to pass
• [x] No new tests required

Checklist

• [x] Code follows the project's coding standards
• [x] Changes are minimal and focused
• [x] No breaking changes
• [x] Documentation not needed (variable name change only)

This is a minor quality-of-life improvement that enhances code readability by fixing the spelling error.