Set CMP0157 to OLD for Android

[Steelskin]

There is no early swift-driver build for the Windows toolchain. As a result, libdispatch fails to build properly when CMP0157 is set to NEW due to object files not being generated.

This sets CMP0157 to OLD when targetting Android until the early swift-driver is available on Windows.

[compnerd]

@swift-ci please test

[Steelskin]

@compnerd Both Linux and Windows are failing on the other issue we were hitting yesterday:

Sources/plutil/CMakeFiles/plutil.dir/PLUContext_KeyPaths.swift.o:main.swift.o:function $sSS6plutilE19escapedKeyPathSplitSaySSGyF: error: undefined reference to '$sSy12RegexBuilderSs11SubSequenceRtzrlE5split9separator9maxSplits25omittingEmptySubsequencesSaySsGSS_SiSbtF'

ICUDateFormatter.swift.obj : error LNK2019: unresolved external symbol __imp_$sSy12RegexBuilderSs11SubSequenceRtzrlE5split9separator9maxSplits25omittingEmptySubsequencesSaySsGSS_SiSbtF referenced in function $s20FoundationEssentials4DateV0A20InternationalizationE11FormatStyleV0C15FieldCollectionV14updateScheduleAD16ICUDateFormatterC0cE4InfoV06UpdateJ0Ovg
ICUDateFormatter.swift.obj : error LNK2019: unresolved external symbol __imp_$sSS17_StringProcessing14RegexComponent0C7BuilderMc referenced in function $sS2S17_StringProcessing14RegexComponent0C7BuilderWl
Duration+UnitsFormatStyle.swift.obj : error LNK2001: unresolved external symbol __imp_$sSS17_StringProcessing14RegexComponent0C7BuilderMc

TimeZone_ICU.swift.obj : error LNK2001: unresolved external symbol __imp_$sSS17_StringProcessing14RegexComponent0C7BuilderMc

At least, the Windows build is progressing further now. I believe fixes have landed for these issues and another run should go even further.

[compnerd]

@swift-ci please test

[compnerd]

Merging this to repair the CI.