Throw TactCompilationError instead Error when possible

[byakuren-hijiri]

Tact compiler throws exceptions when compilation errors occur. Typically, it uses throwCompilationError for this.

This enables the third-party tools to understand the reason of the exception by inspecting the error stacktrace, e.g.:

  static isCompilationError(stack: string | undefined): boolean {
    return stack !== undefined && stack.includes("at throwCompilationError");
  }

The problem is that in some cases we use throw new Error when compilation error occurs. For example, when an unresolved import appears:

tact/src/imports/resolveImports.ts

Line 50 in 2524aae

throw new Error(`Could not resolve import "${i}" in ${path}`);

The idea is to examine all the cases when we throw and to replace them with throwCompilationError or throwInternalCompilerError if possible.

This will be helpful for the tooling and will provide a more unified internal API, fostering debugging of Tact.

[anton-trunov]

This is definitely where we are going to. There is on detail, though. We should provide more info and not just throw TactCompilationError but differentiate between error kinds: parse errors, type errors, etc.