Replace exceptions by strings in the buildscript classpath TAPI model

[bamboo]

During the investigation of #1308, the following stack trace snippet appeared in the Kotlin DSL resolver log:

Caused by: org.gradle.api.UncheckedIOException: java.io.StreamCorruptedException: invalid type code: 61
			at org.gradle.internal.UncheckedException.throwAsUncheckedException(UncheckedException.java:61)
			at org.gradle.internal.UncheckedException.throwAsUncheckedException(UncheckedException.java:41)
			at org.gradle.tooling.internal.provider.serialization.PayloadSerializer.deserialize(PayloadSerializer.java:76)
			at org.gradle.tooling.internal.provider.ProviderConnection.run(ProviderConnection.java:194)
			at org.gradle.tooling.internal.provider.ProviderConnection.run(ProviderConnection.java:135)
			at org.gradle.tooling.internal.provider.DefaultConnection.getModel(DefaultConnection.java:193)

At the top of the stack trace it read:

at org.gradle.tooling.internal.consumer.ExceptionTransformer.transform(ExceptionTransformer.java:55)

Which prompted me to provide this PR as a quick fix to the problem pending some further investigation on its root cause.

[eskatos]

Replacing exceptions by strings in TAPI model is a good move, we can’t control what exceptions will be thrown so we should not expect them all to be “tapi serializable” 👍 💯

This needs more scrutiny before being merged

[eskatos]

Tested with several versions of IJ, works perfectly