Fix culture-dependent ToString in illink tests

[akoeplinger]

We should be emitting the double/float string using invariant culture to avoid failures like this on cultures where decimal point is comma:

Expected:
    ldc.r8 2.5
    ret
Actual:
    ldc.r8 2,5
    ret

[ghost]

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Issue Details

---

We should be emitting the double/float string using invariant culture to avoid failures like this on cultures where decimal point is comma:

Expected:
    ldc.r8 2.5
    ret
Actual:
    ldc.r8 2,5
    ret

Author:	akoeplinger
Assignees:	-
Labels:	linkable-framework
Milestone:	-